udev: re-instate the model-quirks callout

This was removed accidentally as part of a9ef4ba1 and then completely dropped in
870ddce9 when the hwdb was deprecated completely. The model quirks call
is also the one that reads and sets the LIBINPUT_FUZZ property, effectively
making that code a noop.

Fixes #138

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>